The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Vehicles may include a powerplant and an automatic transmission that transmits drive torque at various gear ratios or ranges to a drivetrain. The powertrain may be coupled to the transmission by a torque converter. The transmission may include a gear train that transmits drive torque transmitted by the torque converter at the various gear ratios or ranges. The transmission may further include friction elements, such as clutches, for effecting gear ratio changes during a shift operation. The clutches may be hydraulically actuated and may be controlled by a hydraulic control system.
The shift operation between one or more gear ratios may be one of an up shift or a down shift. The shift operation may further be defined as a power-on shift or a power-off shift. A power-on shift may refer to a shift operation while an accelerator pedal is depressed, while a power-off shift may refer to a shift operation while the accelerator is not depressed.
Transmission control systems have been developed to control fluid pressures supplied by the hydraulic control system to the clutches during shift operations. However, the control systems may decrease the drive torque output by the powerplant to improve shift feel. Decreases in the drive torque can introduce delays in the shift operation and can result in an undesirable sag in drive torque that is perceived by the driver.